Molly

🌍 Overview

Mollies are prolific livebearing fish native to fresh and brackish waters of the southern United States, Mexico, and Central America, closely related to guppies and platies. Unlike most freshwater aquarium fish, mollies naturally inhabit coastal and brackish waters and can tolerate salt concentrations well past normal seawater, a genuine point of difference from their livebearer relatives, though whether a healthy freshwater tank benefits from added aquarium salt is a genuinely disputed question among experienced keepers rather than settled fact. Selective breeding has produced many color and finnage varieties, including the tall-finned sailfin molly.

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📜 History

The common name is a fossil of an obsolete genus. Charles Alexandre Lesueur coined Mollienesia in 1821 in honor of Nicholas Francois, Count Mollien, one of Napoleon's finance ministers, and although a 1963 revision folded the genus into Poecilia, the shortened form stayed attached to the fish. Mollies entered the aquarium hobby around 1905, and the black molly has a contested origin: one account credits a single breeder with seven years of selective work, while another holds that several American breeders arrived at it independently during the 1920s and 1930s, among them Bill Schomberg of Crescent Fish Farm in New Orleans. Today's fancy mollies draw on at least four wild species, which is why their pedigree resists tidy description.

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